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The addition of CO 2 is key to the successful creation of an aquatic plant layout in an aquarium. In some cases, depending upon the type and quantity of plants, aquatic plants can be grown without adding CO 2 to the aquarium, but if you wish to cultivate caulescent or other aquatic plants that require full sunlight, CO 2 will be an indispensable element of the layout. Let's look at some common questions and concerns regarding CO 2 .

Q-1. Why add CO 2 ?

You may wonder why CO 2 (carbon dioxide) should be added to an aquarium. CO 2 is a waste product of respiration for many organisms, and it can even be harmful to the fish and microorganisms in aquarium water. The fact is, though, that plants must have CO 2 for photosynthesis. Aquatic plans absorb the CO 2 , use it to carry out photosynthesis, and, in exchange, release oxygen. This oxygen is then utilized for respiration by the fish and microorganisms. Aquatic plants can supply oxygen far more efficiently than an air pump or other equipment. Therefore, the addition of CO 2 to a tank in which aquatic plants are grown will have the ultimate effect of supplying oxygen to the tank's fish and microorganisms. Plants themselves will not grow and flourish if they cannot engage in photosynthesis. Addition of CO 2 to an aquatic plant layout might best be understood as a step taken not only for the healthy growth of the plants, but also for the health of fish and microorganisms, as well as for the maintenance of a good aquarium environment.

Q-2. What is the best way to add the CO 2 ?

In cases where photosynthesis cannot be expected to proceed very vigorously, such as immediately after the plants have been set, or when the volume of plants is small compared to the size of the tank, only a small amount of CO 2 need be added. However, if the plants start growing and come to occupy a larger proportion of the tank volume as a whole, the amount of CO 2 required for photosynthesis will increase. If you do not add more CO 2 , there will not be enough to sustain photosynthesis, and this process will cease, leading to poor growth of the plants. Accordingly, it is desirable to finely adjust the CO 2 input to reflect the status of plant growth and the condition of the tank. Both excess and insufficient CO 2 are bad for the aquarium environment. In a Nature Aquarium, devices such as the pollen glass atomizer, glass CO 2 bubble counter, and CO 2 regulator are used to diffuse the water with CO 2 siphoned off from a cylinder of liquefied carbon dioxide. The pollen glass atomizes the CO 2 into tiny bubbles so that it will be readily integrated into the water.

Q-3. Why is a counter necessary?

The function of the pollen glass is to atomize the CO 2 for dispersion into the water, but it is difficult to gauge just how much CO 2 has been released. As an indicator of the amount of added CO 2 , you will need a glass CO 2 bubble counter or other type of counter device to measure the CO 2 flow volume. Waterscaping data published in this journal describe CO 2 loading in such terms as “1 drop per second, by glass CO 2 bubble counter.” Here, the measurement tool is the bubble counter, and the unit is one drop per second. Use of measurement tools having identical units gives the data universality, making it possible to determine how much added CO 2 will be appropriate for a tank of the same size under similar growing conditions. For fine adjustment of the CO 2 flow volume itself, a speed controller is indispensable (CO 2 regulators made by ADA come with a built-in speed controller).

Q-4. Why the insistence upon glass?

ADA 's pollen glass atomizers, bubble counters, and other CO 2 addition tools are all made of glass. The reason for this is that glass is stable and exhibits very little deterioration over time; moreover, it is transparent and beautiful to look at. Glass that is just as transparent as the pellucid water that fills a glass aquarium is the ideal material for any tools set up within the tank. Tools and devices made from colored plastic or metal will appear conspicuous within the tank, and the effect can be jarring. For these reasons, ADA aquarium equipment is hand made from durable, ultra-high-transparency glass of the type used in scientific laboratory apparatus. CO 2 addition tools that emit fine bubbles, like the pollen glass, can become soiled from the adhesion of algae on the diffusing surface, and this can clog the holes and lower the diffuser efficiency. Tools made from glass, such as the pollen glass atomizer, have the advantage of being easy to clean with a chlorine-based cleaning solution.